1. Field of the Invention
This invention relates to computer systems and, more particularly, to arrangements for generating addresses at a high clock rate within a computer system.
2. History of the Prior Art
The 80386 microprocessor manufactured by the Intel Corporation, Santa Clara, Calif. is a thirty-two bit microprocessor capable of operating at system clock speeds of sixteen megahertz and above and of addressing a very large address base of four gigabytes of physical memory and sixty-four terrabytes of virtual memory. This microprocessor is capable of operating at very high speeds and processing very large amounts of information as compared to previous processors in the Intel family of microprocessors designed for personal computers.
Although the Intel 80386 microprocessor has been a great success, there have been continual demands for increases in its speed and ability to handle information. Consequently, there have been continuous attempts to improve the speed at which this microprocessor operates. For example, in the Intel 80386 microprocessor the generation of an address which requires an access of memory takes at least two clock periods in the execution stage; therefore, every instruction having a memory reference, that is, one requiring an access of memory in its operation, needs at least two clock periods in the execution stage for processing. This requirement, that two system clock periods be used for each address generation has significantly slowed the operation of the Intel 80386 microprocessor.